The present invention relates to a method of an apparatus for heating and drying a particulate material. More particularly this invention concerns the drying and heating of coal.
A system is known wherein gas is circulated around in a closed circulation path at a superatmospheric pressure. Coal or other particulate material to be dried is introduced into this path at one location and withdrawn downstream therefrom, contacting the gas between these locations and being dried thereby. A burner feeds fresh hot and dry gas into this system in order that the coal is dried. Such arrangements are maintained under superatmospheric pressure in order to prevent oxygen-containing gas from entering the path and combustibly or even explosively combining with the hot coal therein.
Such systems comprise, therefore, two blowers in order to maintain the superatmospheric pressure throughout. Not only does the provision of these two blowers result in elevated system costs, but the running costs are also increased thereby.